Attachment-plug.



G. C. KNAUFF.

ATTACHMENT PLUG.

APPLICATION FILED Nov 2o, 1911.

Patented May 14, 1912.

GEORGE C. KNAUFF, 0F CHICAGO, ILLINOIS.

ATTACHMENT-PLUG'.

Specication of Letters Patent.

Patented May 14, 19t?.

. Application led November 20, 1911. Serial No. 661,375.

To al whom it may concern Be it Anown that I, GEORGE C. KNAUFF, a citizen of the United States, residing at the city of Chicago, in the county of Cook and State of Illinois` have invented a certain new and useful Improvement in Attachmtnt-Plugs, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, which form a part of this specification.

My invention relates tocarriers or supports for wire terminals, such as the attachment plugs for connecting and disconnecting a circuit from a socket or receptacle. In constructing devices of this class, it has heretofore been customary to fasten the wire-carrying terminals in place with screws inserted transversely in the terminals and to depend on a tight driving fit for holding the anchoring element in its proper pos1tion. I have found that the use of such transverse screws weakens the body of the plug and sometimes leads to a grounding between the head of the screw and the metal casing of the socket into which the plug is inserted, particularly in the case pf miniature plugs, such as are used in cronnection with automobile lighting circuits. I have also found that even where the retaining prongs or pins were tightly wedged in place originally, the continued jarring of the vehicle on which such devices are used, would loosen these pins, so that they would either prevent the plugs from being inserted; or from being Withdrawn, if already in the corresponding sockets. l

The object of my invention is to provide a simple construction whereby the contact parts, as well as the anchoring element by lwhich the whole plug is locked in the socket or receptacle, are firmly held in the body of the plug without the need of screws or other auxiliary fastenings. I attain this object by the construction shown in the accompanying drawing, in whichy Figure 1. is a perspective view showing an attachment plug embodying my invention, together with the receptacle as commonly used with such attachment plu s. Fig. 2. is a; vertical section through the nished plug. Fig. 3. is a similar section through the insulating body of the plug before the metal parts have been united with the same. Fig. 4. is asection along the lines 4 4 in Fig. 2.

Fig. 5. is an elevation of one of the terminals of the plug.

In the drawing. A is a receptacle or wallsocket having a flange B for securing the same to a wall or dash board, this recepice being connected to a circuit by wires D is a plug carrying terminals E E for wires F F leading to a lamp or other current consuming device. The cover G, screwed to one end of this plug D, prevents contact between outside objects and the terminals E E as exposed at their junotures with the wires. This cover also forms a. handle by which the plug may be grasped while being inserted into the opening II of the receptacle A, or while being withdrawn from the same. tacle A has slots I I adapted to guide andretain prongs J .I projecting from the sides of the body of the plug D, so as to lock this plug in the position in which the terminals E E contact with terminals of the wires C C.

The body of the plug D is made of an insulating cylinder'- K, composed of some material which may be simultaneously softened and expanded and which will contract in hardening. For this purpose I' preferably use genuine hard rubber which can be thus softened and expanded by being immersed in steam or in water heated nearly to :its boiling point, and which will riontratitland harden when withdrawn from the influence of the steam or hot water. This body D preferably7 has. one end threaded at L to fit threads of the cover G. Perfex-ations M M are bored through the body K parallel to its axis, these perforations being er ual in diameter to the cylindricalends of t e terminals E E. Each terminal E has enlargements, referably in theform oi a raised thread lll on itsmiddle portion and a bore- O at one end for receiving'the tip of a wire. The plug K also has a transverse perforation Q, bored through` it, this bein of the same diameter as the ends J J o the retaining element P, which element I preferably likewise has a raised thread upon it for the greater portion of its length. Each. terminal E has a groove R reducing the diameter at the point which will come opposite the perforation Q, when the parts are assembled. Both the terminal E and the retaining element P are preferably'made of brass, but may be of any materia/l not affect- The casing of the receped by the iniuences used for softening and expanding the body K.

In assembling the parts, I soak the body K in hot water at a temperature of about 200 degrees F., thereby softening and expanding the same. I then insert the terminals E E into the perforations M M by a rotary and gradually advancing motion just as if they were screws, in doing which the threads on E E 'form corresponding threads in the softened walls of the perforations M M. The method which I use for inserting the insertible parts is 'described more fully in my eopending application for a process of uniting materials, Serial #683058, filed March 11, 1912. lThen I similarly screw the retaining element P into the perforation Q, letting it form a corresponding thread in the softened' Walls of Q. On allowing the assembled parts to cool,I the body Kcontr'acts and the portions adjoining the inserted metal parts E E and P, shrink tightly against same. Owing to the large amount of surface offered by the threads, it is practically impossible afterward to move the inserted parts, either by fsteady jarring, or by any twistin or pressure likely to occurv in practice. oreover, the grooves in the terminals E allow the body portion intervening between these terminals along the line 4-4 to expand into the same, thus preserving a thicker Wall of insulating material between these terminals and the pin P, than would be ossible if 36 there were nov grooves in the sur ace of the terminals. If the wires F F are to be soldered to the terminals E E, I preferably provide perforations S S in the hollow ends of the same, through which the surplus sol- 40 der can-flow freely.

What I claim as new and desire to cover bv Letters Iatent is:

1. An electric contact-carrier including an insulating body made of a material adapted to be simultaneously softened and expanded,

and to contract while hardenin a currentcarrier made of a material una ected by the infiuence required to soften and expand the aforesaid body; a perforation in the said body for receiving the said current-carrier;

and enlargements on the said current-carrier which would prevent the same'from being slipped through the said perforation while the said body is in its normal condition; the said enlargements being adapted to.

repress the walls of the perforation when inserted in the said perforation when the body has been softened and expanded, Vand to engage with the said walls when the body contracts in hardening, whereby the said current-carrier is united in fixed relation with the said insulating body.

2. An electric contact-carrier including an insulating body made of a material adapted to be simultaneously' softened and expanded,

.and to contract while hardening; an anchoring element made of a material unaffected by the iniuence required to soften and expand the aforesaid body; a perforation in the said body for receiving the said anchoring element; and enlar ements on the said anchoring element whic would prevent the same from being slipped through the said' perforation while the 'said body is in its normal condition; the said enlargements being adapted to repress the walls of the erforation when inserted in the said per orationK when-the body has been softened and expanded, and to engage with the said walls when the body contracts in hardening, whereby the said anchoring element 1s united in fixed relation with the said insulating body.

3. n an attachment plug, an insulatin body made of a material a apted to be si- 35 multaneously softened and expanded, and to contract while hardening; wire terminals made of material unaffected by the influence used.V to soften and expand the aforesaidv body; perforations in the said body for receiving the said wire-terminals; and an anchorin member inserted through the said insulating body transversely l to the said wire-terminals; the said wire terminals being reduced in section at the portions adjacent tothe said anchoring member; the said anchoring' member being inserted in the transverse' perforation after the said wire terminals have been inserted and while the material of the insulating body is in the softened and expanded state; the said anchoring member having enlargements upon it adapted to expand the walls of the perforation in thc softened body inserted in the same, whereby the material adjoining the said anchoring member is expanded into the recesses formed by the adjacent reduction in size of the wire terminals.

4. In a device of the class described, a body'made of a material adapted to expand 110 when subjected to a softening influence, and to contract and harden when removed from the said softening influence; in combination with current carrying members made of material unaffected by the said softening infiuence; perforations in the said body for receiving the said members; the said members having raised threads, whereby they are adapted to impress threads into the material of the said body member when insorted in the spid body while the same -is in the softened s ate.

5l In a device of the class described, an insulating body made of a material adapted to expand when subjected to a softening infiuence, and to contract and harden when rcmovedv from the said softening infiuence; contact members carried by the said body;

a easing which the said body is adapted to enter; a slot in the said casing leading to 'a 130 seat; and an anchoring element projecting from -the said body; the said anchoring element being adapied to be guided by ille said body to the said sent for anchoring the said body to the said easing; the said anchoring element being rigidly united to the said body by the pressure due to the contraction of the said body after the said element has been inserted in iiiesame while the said body was in the softened end expanded state.

6. In a device of the class described, an insulating body made of a material adapted to expand when subjected to a softening in iuenee, and io contract and harden when removed from the said softening influence;

ber made of material not e'ected by the said softening influence and adapted to be inserted in the said perforation while 'the said body is in the softened and expanded 2o condition; the said member being rigidly united to the said body by the pressure due to the contraction of the said body after the softening influenoe has been removed.

In witness whereof, I have hereunto set my hand, this 14th dav of November A. DL 1911, in thepresence of two subscribing witnesses. Y

GEORGE C. KNAUFF.' Witnesses:

ALBERT SCHEIBLE; CHARLES O. Slammer. 

